DAMASCUS, Syria, May 4 (UPI) -- Israeli warplanes bombed a military research facility in Syria early Sunday, a senior official told NBC News.
It was the second Israeli airstrike in the civil war-torn Middle Eastern country since Friday.
NBC reported a senior U.S. official said the airstrikes were believed to be related to delivery systems for chemical weapons.
CNN said Syrian state TV reported the Syrian government accused Israel of firing rockets into the research center in Jamraya, a suburb of Damascus.
CNN said the Israeli military would not comment on the Syrian TV report.
The Obama administration Saturday denounced the Syrian government after rebel supporters alleged two massacres left about 150 people dead.
The State Department's Jen Psaki said in a statement sharply rebuking the regime of Bashar Assad that the United States was "appalled" by the "horrific reports" of "gruesome" killings of families, including women and children.
"We strongly condemn atrocities against the civilian population and reinforce our solidarity with the Syrian people," Psaki said. "As the Assad regime's violence against innocent civilians escalates, we will not lose sight of the men, women, and children whose lives are being so brutally cut short.
"We call on all responsible actors in Syria to speak out against the perpetration of unlawful killings against any group, regardless of faith or ethnicity. Those responsible for serious violations of international humanitarian law and serious violations and abuses of human rights law must be held accountable."
Activists said 77 people were killed in Baniyas Friday, a day after 72 were killed at the nearby village of al-Bayda, the BBC reported. The attacks led large numbers of Syrians to flee the area.
The government said the deaths in Baniyas resulted from clashes with "terrorist groups," the BBC reported.
Videos posted online show the bodies of women and children, some of them mutilated or partially burned.
Hundreds of families are reported to have fled Baniyas and headed south to the city of Tartus, but have been blocked by the pro-government militia known as the shabbiha.
Anti-regime activists said operations along the coast were an indication of Assad's intention to consolidate his government's position.
In a public appearance Saturday at Damascus University, Assad unveiled a statute honoring "martyred students."
Separately, Israel said its warplanes struck inside Syria Friday, hitting weapons Israel believed were headed to Hezbollah in Lebanon.